Ballistic-type impulse actuator



Sept. 24, 1963 J. M. sAwYER ETAL 3,104,521

BALLISTIC-TYPE IMPULSE ACTUATOR I vFiled April 10, 1961 3 Sheets-Sheet 2 INVENTORS Jouu M.SAWVEIP &

p 1963 J. M. SAWYER ETAL Q 3,104,521

BALLISTIC-TYPE IMPULSE ACTUATOR Filed April 10, 1961 3 Sheets-Sheet 3 FIRE SIGNAL LINE VOLTAGE CONTROL SAFE ARM RELAY LIGHT TRICKLE 6 CHARGER 7 7a DOOR SWH'CH 74- SELECTOR AacEss covea V BATTERY SWTCH SWITCH J 68 CHECKOUT CARTRIDGE CARTRIDGE RELAY 1 69 f CHECKOUT /z /3 LIGHT INVENTORS JOHN Iv. sawyz e Mm r54 5. MEWE/v,

ATTORNEY United States Patent 3,104,521 BALLlSTlC-TYPE lMPULdE ACTUATQR John M. Sawyer and Walter R. Loewen, Dallas, Tex,

assignors, by mesne assignments, to Ling-Tomca- Vought, Inc, Dallas, Tern, a corporation of Delaware Filed Apr. 10, 1961, SenNo. 101,960 6 Claims. (til. oil-26.11)

This invention relates to a ballistic-type impulse actuator.

it is the principal object of the present invention to provide a ballistic-type impulse actuator particularly adapted for opening quickly the surface covered door of a missile launch silo under combat operation conditions.

It is another object of the invention to provide an impulse actuator with self-stored energy in the form of a cartrid e and its alternate cartridge in the breech of the actuator always available to provide when fired high initial piston forces and gas pressures to obtain rapid acceleration of the massive silo door so that the full opening of the door can be efiected in fast actuation time in a matter of seconds, the missile silo door being track mounted and weighing several hundred tons, the actuator having sufiicient force to overcome friction and debris resistance in addition to accelerating the massive door weight and to open the door to the full extent with the actuator Working through an actuator stroke of some thirty-six inches with a minimum velocity at the end of the power stroke of nearly -four feet per second and within two seconds time.

It is still another object of the invention to provide an impulse actuator having the immediately above object in mind which will be capable of effecting two cycles of operation without reloading the cartridge breech, there being provision within the breech for tWo separate cartridges and arranged so that they can be fired in sequence.

It is still another object of the invention to provide an impulse actuator for missile launch silo doors that can receive internal pressures up to ten thousand pounds per square inch in the event of the silo door being blocked tending to stop the piston motion and will have a burning temperature limited to some two thousand degrees Fahrenheit and yet be of a reasonable size and weight that will not require excessive cylinder wall thicknesses or consume great space.

It is still another object of the invention to provide a ballistic-type impulse actuator for use in opening missile launch silo doors that will have incorporated in them a hydraulic snubber to ldecelerate the final :opening and the final closing of the silo door movement.

It is a further object of the invention to provide a ballistic-type missile launch silo door impulse actuator that will be :gas powered from gases released from ballistic cartridges in which two cartridge chambers horizontally-oppose one another and will be covered by spring loaded valves that will protect the unfired cartridge, the cartridges being united by an electric impulse set ofi by a fire control relay system that can fire the cartridges in sequence if second cartridge is needed.

It is a still further object of the invention to provide a gas powered actuator that has a snubber piston incorporated in the main piston and which bottoms on the main piston for the power stroke, and will continue its movement for another twelve inches due to internal gas pressure at the end of the movement of the main piston to the full thirty-six inch stroke of the actuator, hydraulic oil being metered through small orifices to allow full extension of the snubbing piston before the \gas pressure drops to atmosphere pressure by release through a vent in the main piston cylinder wall.

It is a still further object of the invention toprovide a local battery system to provide actuation of the silo door independent of any remote electric control system and including charging equipment to maintain the battery charged for a minimum of ten years.

Other objects of the invention are to provide an impulse silo door gas fired impulse actuator, having the above object in mind, which is simple in operation, has a minimum number of parts, light in weight, easy to load and control, compact, automatic in operation, easy to install, eflicient and elfective in use.

For other objects and a better understanding of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawing, in which FIGURE 1 is a longitudinal semi-schematic sectional view of the ballistic-type impulse actuator where the parts of the actuator are fully retracted, cartridge filled and ready to be fired,

FIG. 2 is a longitudinal sectional view of the impulse actuator with the main piston extended and the silo door partially opened,

FIG. 3 is a longitudinal sectional view of the main and snubber pistons extended and the silo door fully opened,

FIG. 4 is an enlarged sectional View of the impulse actuator with the parts thereof fully retracted and similar to the view shown in FIG. 1 but enlarged to show more of the detail construction,

FIG. 5 is an enlarged longitudinal and fragmentary sectional view of a portion of the actuator showing the snubber piston r'ully retracted in the main piston against the action of its compression spring,

FIG. 6 is a fragmentary and longitudinal sectional view of the main piston head in its fully extended position with the main cylinder end against its sleeve head, and

FIG. 7 is a diagrammatic layout of the fire signal, cartridge selector switch, check out and battery charging system.

Referring now to the figures, ill represents a main fire cylinder of the gas powered impulse actuator embodying the features of this invention and to which there is secured a double cartridge fire head 11 in which is loaded two fire gas-generating cartridges 12 and 13 each of which respectively having a fire detonator 14-. This cartridge head 1-1 is integrally secured by a cylindrical flange 15 to the end of the fire cylinder 1% and has opposing cartnidge chambers 16 and 17 that respectively house the respective cartridges l2 and 13. Opposed valve openings 1S and 19 are disposed between the respective cartridge chambers 16 and 17 and a central valve chamber 20 that supports within it from an integral bearing sup port 21, an opposing double valve assembly 22 having respectively valves 23 and 24 lying in the respective valve openings 18 and 19. These valves 23 and 24 respectively have sleeve shanks 25 and 26 telescopicallyslidable over one another and housing a long compression spring 27 that normally maintains the valves 23 and 24 closed. Upon the firing of a cartridge 12 or 13 its valves 23 or 24 will open to permit the gases to pass into the chamber 21 and upwardly into the main cylinder 10. The valve adjacent to the cartridge that is fired allows the gas to flow from the fired cartridge while the opposite valve is kept closed under pressure of the gas and protects the unfired cartridge from the effect of the hot gas. The spring 27 normally maintains both of the valves closed and will permit the valves to be singly opened. The chambers 16 and 17 are closed by removable heads 14'.

The outer end of the main fire cylinder 10 removed from the cartridge head 11 is provided with a sleeve head 25, tightly secured thereto and made a part of the cylinder 10 and which has a gas sealing O-ring 29 to keep 3 the gases confined within the cylinder and through which a main piston 31 is extended under pressure of the gas that is generated whenone of the cartridges is fired.

This main piston has fixed to its inner end a sleeve piston head 32 having piston rings 33 slidable along the internal wall of the main cylinder 10 and tending to pre vent the escape of gas between the side walls of the pis ton and the main cylinder.

The main piston 31 is hollow and has a head 34 fixed to its inner wall intermediate its length with a central opening 35 and O-ring 36, through which an inner snubber piston 37 slides, FIGS. 4 and 5. This snubber piston 37 is also hollow and has a push head 38 on its outer end for engagement with a silo door 39 which is to be moved by the actuator. The door of the type used in connection with missile-type launch silos weighs several hundred tons and is supported by wheels 49 and 41 on a track 42 as can be best seen in FIGS. 1 and 2, only one side of the door being illustrated. This snubbing piston 37 operates as an extension of the main piston 31 and slides through a head 43 fixed to the outer end of the main piston 31 and is provided with a sealing O-ring 44. This head 43 has an oil filling hole 45 that is closed by a plug 46, FIG. 4.

The snubbing piston 37 carries a round piston plate 48 which is fixed so as to move therewith. This piston plate 43 has an 'O-ring 49 to cut down oil leakage that may tend to pass between the plate 48 and the inner wail of the main piston 31. This plate 48 and the main piston intermediate head 38 will adequately guide the outward movement of the snubbing piston 37. Reacting between the piston head 34 and the piston plate 48 is a compression spring 51 that is loaded by the silo door in order that an initial starting action for the movement of the door will not be so greatly resisted. The amount of movement on compressing the spring 51 is illustrated in FIG. 4 but the full firing action extends the snubbing piston 37 and the piston plate 48 well beyond the spring 51, FIG. 3. A hydraulic chamber 52 has accordingly been provided within the forward end of the main piston 31 and surrounding the snubbing piston 37 and is filled with hydraulic fluid that can meter between opposite sides of the piston plate 48 through metering orifices 53 and 54, FIGS. 4 and 5. The hydraulic fluid is restrained by a ball valve 55 so that there is a How of hydraulic fluid only through the unvalved opening 53 on the return movement of the snubbing piston upon the silo door being closed and the pistons of the actuator being retracted at which time the door is finally closed and a load upon the compression snubber spring 51 is placed.

In FIG. 1, the silo door 39 is shown fully closed and the piston of the impulse actuator fully retracted, the spring 51 being compressed and the cartridge valves 23 and 24 of the valve assembly 22 both closed, the cartridges 12 and 13 are wired in a control system shown in FIG. 7 as will be described later on and fired through their respective detonators 14 by an electrically operated firing pin 56 illustrated in FIG. 2. The cartridge contains ammonium nitrate that is clean burning. Both valves 23 and 24 are spring loaded and are opened automatically by the firing of the cartridge from the force created from its discharge. One cartridge is fired at a time and the valve of the other cartridge protects the other cartridge. It will be seen that the snubbing piston 37 is carried by the main piston assembly 31 as a part thereof, and not only extends to decelerate the door movement at the end of the stroke but will absorb the door momentum when the door is being returned to its closed position. The snubbing action is accomplished as above described by metering hydraulic oil through orifices contained in the plate piston 43 submerged in the hydraulic oil chamber 52.

The power stroke of the impulse actuator is effected by the fire signal which actuates the system control device 56 and transmits an electric impulse to one of the cartridge igniters 14. The cartridge 12 is first ignited and high pressure gases are released to the main piston chamber of cylinder It). The valve 23 opens as shown in FIG. 2 while the valve 24 is kept closed to protect the cartridge from the hot gas resulting from the firing of the cartridge 12. The snubbing piston 37 absorbs the shock of the initial movement of the main piston. The snubbing piston head 38 will be bottomed upon the main piston head 43 as best illustrated in FIGS. 2 and 4 for the main part of the power stroke. The main piston power stroke and the silo piston movement is effected when the gas pressure builds up sufiiciently to overcome the door weight, its rolling friction and debris resistance. As the pressure increases further, the silo doors are accelerated to their peak velocity of about four feet per second and the main stroke is some thirty-six inches.

The door can be fully opened in less than two seconds. The main cylinder head 23 stops the movement of the main piston 31 at the end of the thirty-six inch stroke. The snubber piston 37 continues its movement for an additional twelve inches due to the internal gas pressures Within the main cylinder and within the snubbing piston 37. The hydraulic oil is forced through the check valve 55 and allows for the full extension of the snubbing piston 37. A vent hole 57 in the outer cylinder 10 releases the gas pressures at the end of the main piston stroke. The rate of the gas release is such however to allow for full extension of the snubber piston before the gas pressure is reduced to atmospheric pressure. This impulse actuator completes as seen in FIG. 3 and the snubbing piston 37 is in position to stop the silo door 37 when it is to be returned to its closed position. As the silo door 37 makes contact with the snubber piston on its return roll, this snubber piston acts as a shock absorber. The hydraulic oil is forced through orifice 53 and the snubbing piston will then decelerate the silo door. When the door is closed, the spring 51 on the snubber piston keeps the snubbing piston head 38 in contact with the silo door 39. The impulse actuator is then ready to be fired again. The silo door 39 is held open by a latch shoulder 58 on the door 39 that engages an electrically-controlled latch stop 59.

Referring now to FIG. 7, it will be noted that an independent battery system can be used by which the ballistic impulse actuator will be ignited where there is no other power source available from the silo. A battery 65 is maintained at its proper voltage level by a trickle charger 66 from a line voltage 67. A nickel-cadmium battery with a trickle charger will hold a full charge for a minimum of ten years.

An electric switch 68 automatically switches from the first cartridge 12 to the second cartridge 13 for the firing thereof. A check out relay 69 and a check out light 71 are provided in the control system to continuously check the electric circuits. The electrical system may be however modified to fit the requirements of the installation. All of the electric components shown in the diagram may be enclosed in a single control box to facilitate the maintenance and check out of the system. The box may have an interchangeable panel that will expedite and make easy the replacement of the equipment.

A safety light 72 is provided in the system to give indication that the main silo door is positioned and that the access cover is closed preparatory to firing. An access door control switch 73 is provided in the system to afford protection to personnel while checking the system. The door latch stop 59 and the silo door 39 are controlled by a door switch 74. When both the cover and the doors are in place battery power is available to a control relay 75 and the safe arm light 72 indicates this condition. Upon a fire signal 76 being brought into play, control relay 75 supplies energy to the tire circuit for igniting one of the cartridges, that is, the first cartridge 12. The

selector switch 68 is thereafter operated to automatically switch over the fire signal to the other cartridge 13. The second cartridge 13 is then ready for firing to complete the opening of the silo door. If for any reason the first cartridge fails to fire, the automatic feature of the selector switch switches the fire to the other cartridge. A second fire signal then energizes the other cartridge 13. The check out system permits the checking of the cartridges with a reduced voltage which will indicate the condition of the electric system but will not set ofi the igniter.

While various changes may be made in the detailed construction, it shall be understood that such changes shall be within the spirit and scope of the present invention as defined by the appended claims.

What is claimed is:

1. An impulse actuator comprising a cartridge breech head adapted to receive gas creating cartridges, a main cylinder extending from the breech head, a hollow main piston operable in the main cylinder, a head disposed within the main cylinder intermediate its length, a head on the outer end of the piston, a hollow snubbing piston slidable through said main piston heads, the outer end of said main piston providing a hydraulic chamber, a metering plate fixed to the snubbing piston and operable in the hydraulic chamber, said metering head allowing for the extension of the snubbing piston under the pressure of the gas created from the discharge of the cartridge to effect deceleration of the object being moved at the end of the stroke, and said cartridge breech head having laterally opposed cartridge chambers for receiving said cartridges and laterally opposed valve openings leading from the respective chambers, and opposed spring biased valve elements lying Within the opposed openings and operable to individually operate upon discharge of the corresponding cartridges.

2. An impulse actuator for moving an object comprising, a cartridge breech head having diametrically opposed cartridge chambers each adapted to receive a gas creating cartridge, a main cylinder extending from the breech head, opposed valve openings leading from the cartridge chambers toward one another into the main cylinder, opposing dual valve means mounted in said valve openings with one valve being operable at a time independently of the other valve, a hollow main piston operable in the main cylinder, a slidable head disposed Within the main piston intermediate its length, a head on the outer end of the main piston, a hollow snubbing piston slidable through said main piston heads, a hydraulic chamber within said hollow main piston between said slidable head and said head on the outer end of the main piston, and a metering plate fixed to said snubbing piston and operable in the hydraulic chamber, said metering head allowing for the extension of the snubbing piston under the pressure of the gas created from the discharge of one of the cartridges to effect deceleration of the object being moved at the end of the stroke of said snuhhing piston.

3. An impulse actuator as defined in claim 2, and said opposing dual valve means each including valve heads at their outer ends to close said valve openings and including inner shank portions telescoping into one another from the respective openings and slidable over one anothor upon a valve being actuated, and a biasing spring disposed in the shank portions and tending to bias the valve heads closed within the valve openings but permitting movement of one valve means relative to the other, and central support means Within the breech block for supporting the valve means.

4. An impulse actuator as defined in claim 2, and a fire signal control system including detonators for the respective cartridges and a selector control switch after the firing of one cartridge to automatically condition the systemfor the firing of the other cartridge in sequence.

5. An impulse actuator according to claim 4, wherein said fire control system further includes a battery supply and charging circuit means with a control relay door, and access cover switches and a safety arm light indicator to indicate the condition of the door and access cover preparatory to the firing of the impulse actuator.

6. An impulse actuator as defined in claim 5, and a check out relay and light circuit operable from a battery to indicate the condition of the battery and selector firing circuits of the system.

References Cited in the file of this patent UNITED STATES PATENTS Werle et a1 Dec. 5, 

2. AN IMPULSE ACTUATOR FOR MOVING AN OBJECT COMPRISING, A CARTRIDGE BREECH HEAD HAVING DIAMETRICALLY OPPOSED CARTRIDGE CHAMBERS EACH ADAPTED TO RECEIVE A GAS CREATING CARTRIDGE, A MAIN CYLINDER EXTENDING FROM THE BREECH HEAD, OPPOSED VALVE OPENINGS LEADING FROM THE CARTRIDGE CHAMBERS TOWARD ONE ANOTHER INTO THE MAIN CYLINDER, OPPOSING DUAL VALVE MEANS MOUNTED IN SAID VALVE OPENINGS WITH ONE VALVE BEING OPERABLE AT A TIME INDEPENDENTLY OF THE OTHER VALVE, A HOLLOW MAIN PISTON OPERABLE IN THE MAIN CYLINDER, A SLIDABLE HEAD DISPOSED WITHIN THE MAIN PISTON INTERMEDIATE ITS LENGTH, A HEAD ON THE OUTER END OF THE MAIN PISTON, A HOLLOW SNUBBING PISTON SLIDABLE THROUGH SAID MAIN PISTON HEADS, A HYDRAULIC CHAMBER WITHIN SAID HOLLOW MAIN PISTON BETWEEN SAID SLIDABLE HEAD AND SAID HEAD ON THE OUTER END OF THE MAIN PISTON, AND A METERING PLATE FIXED TO SAID SNUBBING PISTON AND OPERABLE IN THE HYDRAULIC CHAMBER, SAID METERING HEAD ALLOWING FOR THE EXTENSION OF THE SNUBBING PISTON UNDER THE PRESSURE OF THE GAS CREATED FROM THE DISCHARGE OF ONE OF THE CARTRIDGES TO EFFECT DECELERATION OF THE OBJECT BEING MOVED AT THE END OF THE STROKE OF SAID SNUBBING PISTON. 